問題一：出現Attempting to operate on hdfs namenode as root
寫在最前注意：
1、master，slave都需要修改start-dfs.sh，stop-dfs.sh，start-yarn.sh，stop-yarn.sh四個文件
2、如果你的Hadoop是另外啟用其它用戶來啟動，記得將root改為對應用戶
HDFS格式化后啟動dfs出現以下錯誤：
[root@master sbin]# ./start-dfs.sh Starting namenodes on [master] ERROR: Attempting to operate on hdfs namenode as root ERROR: but there is no HDFS_NAMENODE_USER defined. Aborting operation. Starting datanodes ERROR: Attempting to operate on hdfs datanode as root ERROR: but there is no HDFS_DATANODE_USER defined. Aborting operation. Starting secondary namenodes [slave1] ERROR: Attempting to operate on hdfs secondarynamenode as root ERROR: but there is no HDFS_SECONDARYNAMENODE_USER defined. Aborting operation.
查度娘，見一仁兄的博客有次FAQ，故參考處理順便再做一記錄
參考地址：https://blog.csdn.net/u013725455/article/details/70147331
在/hadoop/sbin路徑下：
將start-dfs.sh，stop-dfs.sh兩個文件頂部添加以下參數
HDFS_DATANODE_USER=root
HDFS_DATANODE_SECURE_USER=hdfs
HDFS_NAMENODE_USER=root
HDFS_SECONDARYNAMENODE_USER=root
還有，start-yarn.sh，stop-yarn.sh頂部也需添加以下：
#!/usr/bin/env bash YARN_RESOURCEMANAGER_USER=root HADOOP_SECURE_DN_USER=yarn YARN_NODEMANAGER_USER=root # Licensed to the Apache Software Foundation (ASF) under one or more
修改后重啟 ./start-dfs.sh，成功！
[root@master sbin]# ./start-dfs.sh WARNING: HADOOP_SECURE_DN_USER has been replaced by HDFS_DATANODE_SECURE_USER. Using value of HADOOP_SECURE_DN_USER. Starting namenodes on [master] 上一次登錄：日 6月 3 03:01:37 CST 2018從 slave1pts/2 上 master: Warning: Permanently added 'master,192.168.43.161' (ECDSA) to the list of known hosts. Starting datanodes 上一次登錄：日 6月 3 04:09:05 CST 2018pts/1 上 Starting secondary namenodes [slave1] 上一次登錄：日 6月 3 04:09:08 CST 2018pts/1 上
from: https://blog.csdn.net/lglglgl/article/details/80553828
問題二：正常啟動后jps查看無namenode,datanode
解決方法：
1.先查看是不是的防火牆開啟，將防火牆關閉：service iptbales stop
2.查看端口狀態：telnet 192.168.86.10 9000（192.168.86.10是我自己的靜態ip）
如果出現不能連接，那么我們需要修改我們的hosts
3.修改hosts：vi /etc/hosts
將127：0：0：1 localhost localhost.localdomain localhost4 localhost4.localdomain4
改為 ：：1 localhost localhost.localdomain localhost4 localhost4.localdomain4
或者將127：0：0：1 localhost localhost.localdomain localhost4 localhost4.localdomain4 刪除
在下方寫入 192.168.86.10 mini1 localhost (192.168.86.10是我自己的靜態ip mini1是我的主機名)
4.重新啟動network：service network restart或sudo /etc/init.d/networking restart
from: https://blog.csdn.net/u010599953/article/details/75635058